WIP: Implement deep freeze and freeze for namespaces

CHANGELOG.md

@@ -8,6 +8,8 @@ and this project adheres to
 
 ## [Unreleased][unreleased]
 
+- Implement `deepFreeze` and `freezeNamespaces`
+
 ## [2.2.0][] - 2020-07-10
 
 ### Added

README.md

@@ -188,6 +188,8 @@ $ npm install @metarhia/common
 - [parseHost](#parsehosthost)
 - [override](#overrideobj-fn)
 - [mixin](#mixintarget-source)
+- [deepFreeze](#deepfreezeinstance)
+- [freezeNamespaces](#freezenamespacesnamespaces-skipnames)
 - [Pool](#class-pool)
   - [Pool.prototype.constructor](#poolprototypeconstructorfactory--null)
   - [Pool.prototype.get](#poolprototypeget)
@@ -1334,6 +1336,24 @@ Previous function will be accessible by obj.fnName.inherited
 
 Mixin for ES6 classes without overriding existing methods
 
+### deepFreeze(instance)
+
+- `instance`: [`<Object>`][object] target nested objects structure
+
+_Returns:_ [`<Object>`][object] - deep freezed instance
+
+Deep freeze object structure
+
+### freezeNamespaces(namespaces, skipNames)
+
+- `namespaces`: [`<Object>`][object] target nested objects structure
+- `skipNames`: [`<Array>`][array] nemes to be skipped for freezing at first
+  level
+
+_Returns:_ undefined
+
+Deep freeze namespaces
+
 ### class Pool
 
 #### Pool.prototype.constructor(factory = null)

lib/oop.js

@@ -23,7 +23,43 @@ const mixin = (target, source) => {
   Object.assign(target, mix);
 };
 
+const REF_TYPES = ['object', 'function'];
+
+// Deep freeze object structure
+//   instance - <Object>, target nested objects structure
+// Returns: <Object> - deep freezed instance
+//
+const deepFreeze = instance => {
+  Object.freeze(instance);
+  const fields = Object.getOwnPropertyNames(instance);
+  for (const fieldName of fields) {
+    const value = instance[fieldName];
+    if (value === null) continue;
+    if (!REF_TYPES.includes(typeof value) || Object.isFrozen(value)) continue;
+    deepFreeze(value);
+  }
+  return instance;
+};
+
+// Deep freeze namespaces
+//   namespaces - <Object>, target nested objects structure
+//   skipNames - <Array>, nemes to be skipped for freezing at first level
+// Returns: undefined
+//
+const freezeNamespaces = (namespaces, skipNames = []) => {
+  for (const namespace of namespaces) {
+    const names = Object.keys(namespace);
+    for (const name of names) {
+      const target = namespace[name];
+      if (skipNames.includes(name)) continue;
+      deepFreeze(target);
+    }
+  }
+};
+
 module.exports = {
   override,
   mixin,
+  deepFreeze,
+  freezeNamespaces,
 };